Minimum Experience for Rebreather Training
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broncobowsher
Contributor
I go with advance Nitrox and Deco procedures.
The rebreather is a continuous Nitrox blender on your back (or chest, etc.). It really is best to have the basics of Nitrox out of the way and advanced Nitrox since you will be dealing with 100% O2 during the dive. Yes, it can be rolled into the rebreather class, but there is so much to the rebreather that it really is best to have that out of the way ahead of time. I would consider that an absolute minimum. So really that is basic Nitrox and advanced Nitrox, two different Nitrox classes.
Next is Deco procedures. For a couple of reasons. The basic one, you will have so much more time potential in the water that deco is very probable. It is commonly paired with advanced Nitrox as they go hand in hand. This will help teach the dive planning that is needed with a rebreather.
If you don't have those out of the way ahead of time it will really make the rebreather class much more difficult.
If you think of open circuit as a driver's license, a rebreather cert is more like a pilot's license. With a driver's license you can drive any make/model of car. Pilot's license you get checked out for each aircraft you are going to fly. So getting trained on a JJ will get you training on a JJ. But not a rEvo. Each different rebreather you get signed off on takes a crossover course. The initial course teaches the basics and the specifics of that one rebreather. The crossover will teach the specifics of a different rebreather. So there tends to be a lot of research into which rebreather you think will be right the first time. Don't really want to spend a ton of money getting trained on a model that you will never use.
Now back to where you state you are interested in a rebreather. No other specifications, reasons, plans, etc...
Many instructors will offer try-dives. Sometimes in bulk with several other people. It's the next level of try-scuba. Expect to pay a little bit for the experience. I did one a dozen years ago when Poseidon started marketing there new rebreather. They were doing a cross country tour. It was in a city pool. It was an experience. I could tell there were some things I liked, and some I didn't. But it got me into the research phase with a hint of experience. I would highly recommend getting in on one of these if you can. For a first experience I would say any model is fine. Just try one. Look around, there are rebreather divers all over the place these days. About the only bad time to try and talk to them is when they are gearing up and trying to get into the water.
The rebreather is a continuous Nitrox blender on your back (or chest, etc.). It really is best to have the basics of Nitrox out of the way and advanced Nitrox since you will be dealing with 100% O2 during the dive. Yes, it can be rolled into the rebreather class, but there is so much to the rebreather that it really is best to have that out of the way ahead of time. I would consider that an absolute minimum. So really that is basic Nitrox and advanced Nitrox, two different Nitrox classes.
Next is Deco procedures. For a couple of reasons. The basic one, you will have so much more time potential in the water that deco is very probable. It is commonly paired with advanced Nitrox as they go hand in hand. This will help teach the dive planning that is needed with a rebreather.
If you don't have those out of the way ahead of time it will really make the rebreather class much more difficult.
If you think of open circuit as a driver's license, a rebreather cert is more like a pilot's license. With a driver's license you can drive any make/model of car. Pilot's license you get checked out for each aircraft you are going to fly. So getting trained on a JJ will get you training on a JJ. But not a rEvo. Each different rebreather you get signed off on takes a crossover course. The initial course teaches the basics and the specifics of that one rebreather. The crossover will teach the specifics of a different rebreather. So there tends to be a lot of research into which rebreather you think will be right the first time. Don't really want to spend a ton of money getting trained on a model that you will never use.
Now back to where you state you are interested in a rebreather. No other specifications, reasons, plans, etc...
Many instructors will offer try-dives. Sometimes in bulk with several other people. It's the next level of try-scuba. Expect to pay a little bit for the experience. I did one a dozen years ago when Poseidon started marketing there new rebreather. They were doing a cross country tour. It was in a city pool. It was an experience. I could tell there were some things I liked, and some I didn't. But it got me into the research phase with a hint of experience. I would highly recommend getting in on one of these if you can. For a first experience I would say any model is fine. Just try one. Look around, there are rebreather divers all over the place these days. About the only bad time to try and talk to them is when they are gearing up and trying to get into the water.
Great, thanks for the detailed reply. I already dive Nitrox but I've always stayed within my NDLs so I'll look into the suggestions you made. Even if I never do anything else besides OC diving, and never strap on a rebreather, I think the deco training is worth doing because it will give me another level of theory knowledge. And if I ever run into a problem at depth that delays my ascent unexpectedly, it may save my life.
Using a rebreather involves quite a lot of extra hassle. Even keeping the kit current, cells expire, many more cylinders need to be o2 clean and in test, is a pain. Yesterday I was thinking “should I get this cylinder tested and so dump a load of trimix, or bet if I have to bailout (using that gas) on a trip later in the year that I can rent an in-test cylinder?”. people will say “you ought to be practicing bailing out anyway” which is true, but in practice a challenge If not getting enough of the right kind of dive.Yeah, I see that LOL. Like I said, just curious for future bucket list of things to try. Maybe, I'll try sidemount first
A rebreather is not just for Christmas, it is for life.
I agree with @KenGordon , it’s extra prep time, for every day diving.Yeah, I see that LOL. Like I said, just curious for future bucket list of things to try. Maybe, I'll try sidemount first
I’d only do this if your plan is to do deeper dives, because that’s where the pros start beating the cons.
I.e, if I stayed at the 40m range and/or didn’t want to dive regularly deeper, I’d just stay on a OC twinset myself.
Transitioning to a rebreather... what I learned.
You need decent core skills: buoyancy, finning, trim. No point in starting with CCR if you haven't got these sorted.
You will be switching from the rebreather to open circuit (bailout) and back again a lot during training and thereafter. You need to be comfortable with switching mouthpieces and carrying a bailout cylinder on every dive.
Rebreathers are complicated as they're basically gas mixing machines. You will have to learn about gases, partial pressures, oxygen issues (poisoning, max operating depth), etc. Most of this is covered along with gas switching protocols in the Advanced Nitrox and Decompression Procedures course which, IMHO, really should be considered a pre-requisite for rebreather diving.
Other than that, there's the subtle issues. You MUST be a bit pedantic about your equipment preparation. You need to spend time the previous evening preparing your kit: filling the scrubber(s), cylinders, cleaning, building, testing, checking... Allow 2 hours and think ahead for gas fills. Use a written checklist and keep notes of the readings (cell millivolts, weighting, battery levels, etc.)
You must put the time in to gain experience on the unit. Basically you have to do a lot of time on the unit and do a lot of ascents (the hardest part of diving a rebreather).
Buoyancy is very different on CCR. You eventually will get the hang of it again.
Small mention of maintenance costs. Cells need replacing so budget for 3 a year. Sofnolime costs money; you need to have a keg or two in stock (or you won't be diving).
CCR has many failure modes and you must continually monitor it. Complacency kills. Many (most?) CCR divers have some form of complacency incident around 50 to 100 hours. Just when you think you've mastered it, BOOM, it reminds you who's boss.
And the good stuff: CCR is fantastic in the water compared with open circuit. It's quieter, no bubbles, the fish aren’t bothered by your bubbles, it’s far more stable, low gas consumption and therefore cheap rich helium mixes, 'unlimited' gas availability. In short it's so much nicer than diving open circuit.
You need decent core skills: buoyancy, finning, trim. No point in starting with CCR if you haven't got these sorted.
You will be switching from the rebreather to open circuit (bailout) and back again a lot during training and thereafter. You need to be comfortable with switching mouthpieces and carrying a bailout cylinder on every dive.
Rebreathers are complicated as they're basically gas mixing machines. You will have to learn about gases, partial pressures, oxygen issues (poisoning, max operating depth), etc. Most of this is covered along with gas switching protocols in the Advanced Nitrox and Decompression Procedures course which, IMHO, really should be considered a pre-requisite for rebreather diving.
Other than that, there's the subtle issues. You MUST be a bit pedantic about your equipment preparation. You need to spend time the previous evening preparing your kit: filling the scrubber(s), cylinders, cleaning, building, testing, checking... Allow 2 hours and think ahead for gas fills. Use a written checklist and keep notes of the readings (cell millivolts, weighting, battery levels, etc.)
You must put the time in to gain experience on the unit. Basically you have to do a lot of time on the unit and do a lot of ascents (the hardest part of diving a rebreather).
Buoyancy is very different on CCR. You eventually will get the hang of it again.
Small mention of maintenance costs. Cells need replacing so budget for 3 a year. Sofnolime costs money; you need to have a keg or two in stock (or you won't be diving).
CCR has many failure modes and you must continually monitor it. Complacency kills. Many (most?) CCR divers have some form of complacency incident around 50 to 100 hours. Just when you think you've mastered it, BOOM, it reminds you who's boss.
And the good stuff: CCR is fantastic in the water compared with open circuit. It's quieter, no bubbles, the fish aren’t bothered by your bubbles, it’s far more stable, low gas consumption and therefore cheap rich helium mixes, 'unlimited' gas availability. In short it's so much nicer than diving open circuit.
I have been thinking about this and I believe it doesn’t matter. You could transition to CCR almost from the start and build all your skills there. Only downside it will be much harder and expensive to find instructors that can help you build your skills. This is probably the reason why many get to a high level in OC and then transition. The fundamentals are the same, with some differences for buoyancy control.
mderrick
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Quoting from Rebreather Training
Historically, the rebreather training course was considered to be at the pinnacle of technical training with extensive prerequisites and contained an almost overwhelming amount of information; much of it being of questionable value and some information being of questionable veracity. However, modern rebreather training standards have both lowered the entry level prerequisites and raised the prerequisites for advancement; spreading the content over a safer progression of courses that allows for better skills development and knowledge retention. CCR accident analysis has improved the information content to focus on safety, and recent research has dispelled some of the misleading 'conventional wisdom' surrounding rebreathers. Today, to become a certified rebreather diver you need only be a certified sport Nitrox diver, although I also recommend "Deep" and "Rescue" sport diving certifications; as a practical matter you should also have some recent dive experience.
Rebreathers are revolutionizing technical diving, and many open circuit technical divers are considering switching to CCR. However, too rapid progression in CCR diving has been a factor in many accidents and now it is no longer possible to just "cross over" the highest level certification from open circuit technical diving directly to the closed circuit equivalent. Modern rebreather training guidelines require the open circuit technical training courses to be repeated in a slow progression of closed circuit versions. Although guidelines allow entry level rebreather training to include required decompression stops, best practice would be for all divers who wish to perform such dives first build some no-stop required experience with their rebreather. If you are currently a sport diver who expects to progress in to technical CCR diving, there is no significant advantage to completing any open circuit technical training before rebreather training.
Highly experienced divers switching to CCR often have an additional challenge: they must overcome their deeply ingrained open circuit mind-set and habits regarding dive planning, equipment configuration, breathing patterns, buoyancy control and gas management.
Historically, the rebreather training course was considered to be at the pinnacle of technical training with extensive prerequisites and contained an almost overwhelming amount of information; much of it being of questionable value and some information being of questionable veracity. However, modern rebreather training standards have both lowered the entry level prerequisites and raised the prerequisites for advancement; spreading the content over a safer progression of courses that allows for better skills development and knowledge retention. CCR accident analysis has improved the information content to focus on safety, and recent research has dispelled some of the misleading 'conventional wisdom' surrounding rebreathers. Today, to become a certified rebreather diver you need only be a certified sport Nitrox diver, although I also recommend "Deep" and "Rescue" sport diving certifications; as a practical matter you should also have some recent dive experience.
Rebreathers are revolutionizing technical diving, and many open circuit technical divers are considering switching to CCR. However, too rapid progression in CCR diving has been a factor in many accidents and now it is no longer possible to just "cross over" the highest level certification from open circuit technical diving directly to the closed circuit equivalent. Modern rebreather training guidelines require the open circuit technical training courses to be repeated in a slow progression of closed circuit versions. Although guidelines allow entry level rebreather training to include required decompression stops, best practice would be for all divers who wish to perform such dives first build some no-stop required experience with their rebreather. If you are currently a sport diver who expects to progress in to technical CCR diving, there is no significant advantage to completing any open circuit technical training before rebreather training.
Highly experienced divers switching to CCR often have an additional challenge: they must overcome their deeply ingrained open circuit mind-set and habits regarding dive planning, equipment configuration, breathing patterns, buoyancy control and gas management.
Praise be
CCR is complicated. Very complicated. It has to be mastered with plenty of time honing skills and problem solving underwater. Forgetting to turn on the oxygen does happen with tragic consequences (worse still failing to notice all the warnings, possibly because you’re so distracted with something else)
kaylee_ann
crazy diver
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